US9850900B2 - Rotary compressor and rotation mechanism - Google Patents

Abstract

A rotary compressor, comprising: a housing, comprising a lubricant oil storage part for containing lubricating oil; a compression mechanism disposed in the housing; a driving mechanism driving the compression mechanism, the driving mechanism comprising a rotation shaft, through-holes extending along the axial direction of the rotating shaft are disposed inside the rotating shaft, and the rotation shaft is in fluid connection with the lubricating oil storage part via the through-holes; and an oil level sensor in fluid connection with the through-holes inside the rotation shaft via a pressurized collection channel. Also disclosed is a rotation mechanism, comprising an oil level sensor in fluid connection with the through-holes inside the rotation shaft via the pressurized collection channel. Accurate and reliable detection of the lubricating oil in a compressor can be done using the pressurized collection channel and the oil level sensor, thus greatly saving cost and improving compressor reliability.

Description

The present application is the national phase of International Application No. PCT/CN2012/074247, titled “ROTARY COMPRESSOR AND ROTARY MECHANISM”, filed on Apr. 18, 2012, which claims the priorities to Chinese patent application No. 201110104725.1 titled “ROTARY COMPRESSOR AND ROTARY MACHINE”, filed with the Chinese State Intellectual Property Office on Apr. 18, 2011 and Chinese patent application No. 201120124863.1 titled “ROTARY COMPRESSOR AND ROTARY MACHINE”, filed with the Chinese State Intellectual Property Office on Apr. 18, 2011. The entire disclosures thereof are incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to a rotary compressor and a rotary machine.

BACKGROUND OF THE INVENTION

The rotary compressor generally comprises a shell, a compressing mechanism disposed in the shell, a driving mechanism for driving the compressing mechanism and so on. In order to ensure the normal operation of the compressor, there must be sufficient lubricating oil in the compressor. The lubricating oil level in the compressor should be higher than a lowest protection lubricating oil level. When the lubricating oil level in the compressor is lower than the lowest protection lubricating oil level, the compressor should be shut off.

A twin compressor system or even a multiple compressor system has been used widely. In this kind of twin or multiple compressor system, one or more of the compressors may be activated selectively and the others may be shut off, therefore lubricating oil would move in these compressors which may cause lubricating oil unbalance among compressors, even results in a situation that some compressors lack of lubricating oil.

In addition, lacking of lubricating oil may occur due to oil leakage in the compressor or oil leakage in the compressor system consisting of a single compressor or a plurality of compressors.

Furthermore, in the large refrigeration system having long pipeline and a great number of components, the lubricating oil may be unable to circulate back to the compressor in time, which causes lubricating oil shortage in the compressor.

As a result, the lubricating oil status (for example, height of lubricating oil level) in the compressor must be detected accurately to shut off the compressor timely and prevent the compressor from being damaged.

SUMMARY OF THE INVENTIONTechnical Problems to be Solved

However, most of the compressors have no built-in oil level sensor presently.

Although there are some liquid level sensors for detecting liquid level, these liquid level sensors are only suitable for detecting the liquid level in an oil tank or in a container. These sensors includes: piezoelectric liquid level sensor, reed switches liquid level sensor, ultrasonic liquid level sensor, photoelectric liquid level sensor and so on. The above mentioned sensors generally cannot be used in a hermetic compressor, since the working environment within the hermetic compressor is rigorous. For example, the ranges of the temperature and the pressure within the compressor are wide, and the pressure and the temperature would cycle, and there may be cast impurity etc. In addition, lubricating oil foam may be formed in the compressor. Therefore, these sensors cannot detect height of lubricating oil level accurately.

Accordingly, there is a need for a rotary compressor which can detect lubricating oil in the compressor more simply and reliably.

Technical Solutions

An object of one or more embodiments of the disclosure is to provide a rotary compressor which can detect lubricating oil within the compressor simply and reliably.

Another object of one or more embodiments of the disclosure is to provide a rotary machine which can detect lubricating oil within the rotary machine simply and reliably.

One aspect of the description provides a rotary compressor, comprising a shell including an oil sump for receiving lubricating oil; a compressing mechanism disposed in the shell; a driving mechanism for driving the compressing mechanism, the driving mechanism includes a rotary shaft provided therein with a through hole extending in an axial direction of the rotary shaft and the rotary shaft is in fluid communication with the oil sump via the through hole; and an oil level sensor in fluid communication with the through hole in the rotary shaft through a pressure picking passage.

Preferably, the rotary compressor further comprises a lower bearing housing for supporting the rotary shaft, wherein the pressure picking passage comprises a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft, a circumferential oil groove formed on the rotary shaft or the lower bearing housing and in fluid communication with the pressure picking hole, and a communicating channel extending through the lower bearing housing and in fluid communication with the circumferential oil groove and the oil level sensor.

Preferably, the rotary compressor further comprises a pressure picker disposed between the rotary shaft and the oil level sensor, wherein the pressure picking passage comprises a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft, a circumferential oil groove formed on the rotary shaft or the pressure picker and in fluid communication with the pressure picking hole, and a communicating channel extending through the pressure picker and in fluid communication with the circumferential oil groove and the oil level sensor.

Preferably, the pressure picking passage further comprises a pressure picking pipe disposed in the pressure picking hole and protruded toward an axis of the through hole in the rotary shaft.

Preferably, a length of the pressure picking pipe is determined according to a lowest protection lubricating oil level in the oil sump.

Preferably, the higher the lowest protection lubricating oil level is set, the longer the length of the pressure picking pipe is set.

Preferably, the lowest protection lubricating oil level and the length of the pressure picking pipe satisfy the following equation:

$H=h-\frac{{\left(R-L\right)}^2·{\left(\frac{\mathrm{<figure-callout\; label="n"\; filenames="US09850900-20171226-D00001.png"\; state="\{\{state\}\}">n</figure-callout>}}{60}·2\pi \right)}^2}{2000·g},$
wherein, H [mm] is a height of the lowest protection lubricating oil level from an end face of the rotary shaft; L[mm] is a length of the pressure picking pipe protruded into the rotary shaft; R [mm] is an inner radius of the rotary shaft; h [mm] is a height of a central axis of the pressure picking pipe from the end face of the rotary shaft; n [rpm] is the number of revolution of the rotary shaft; g [m/s²] is the acceleration of gravity.

Preferably, a height of the pressure picking hole from a certain reference surface (S) is determined according to the lowest protection lubricating oil level in the oil sump.

Preferably, the higher the lowest protection lubricating oil level is set, the higher the height of the pressure picking hole is set.

Preferably, the reference surface is a bottom surface of the rotary compressor or an end surface of the rotary shaft.

Preferably, the rotary compressor further comprises an oil pumping mechanism which includes a plate with a hole provided at an end of the rotary shaft and an oil fork provided in the through hole of the rotary shaft.

Preferably, the oil pumping mechanism includes a vane pump provided at an end of the rotary shaft.

Preferably, the rotary compressor is a horizontal rotary compressor and an inner space of the rotary compressor is divided into high side acting as the oil sump and low side by a muffler plate, and the oil pumping mechanism is an oil pipe extending from the oil sump to the through hole in the rotary shaft.

Preferably, the through hole comprises a concentric hole portion which is concentric with respect to the rotary shaft and an eccentric hole portion which is offset radially with respect to the concentric hole.

Preferably, the oil level sensor is a pressure sensor.

Preferably, the oil level sensor is a pressure switch.

Preferably, the oil level sensor comprises: a fluid pressure receiving portion for receiving pressure of fluid; and a converting portion for converting the pressure of fluid into an electrical signal.

Preferably, the fluid pressure receiving portion comprises a housing and a piston head which is movable axially in the housing; the converting portion comprises a terminal plug, a first contact and a second contact provided in the terminal plug, a spring for providing electrical connection between the piston head and the second contact and providing return force for the piston head, wherein the oil level sensor outputs the electric signal when the piston head contacts the first contact.

Preferably, the first contact comprises a plurality of pins which are spaced with each other.

Preferably, the second contact comprises an annular contact lug electrically contacted with the spring.

Preferably, the rotary compressor further comprises an oil temperature sensor.

Preferably, the oil temperature sensor and the oil level sensor have a common lead wire.

Preferably, the oil level sensor is provided near the lower bearing housing.

Preferably, the oil level sensor is directly connected with the communicating channel in the lower bearing housing or in the pressure picker.

Preferably, the oil level sensor is connected with the communicating channel in the lower bearing housing or in the pressure picker through an additional pipeline.

Preferably, the rotary compressor is a scroll compressor, or a screw compressor, or a rotor compressor.

Preferably, the oil level sensor is disposed inside the shell or outside the shell.

Preferably, when the oil level sensor is disposed outside the shell, the pressure picking passage further comprises a connecting pipe in fluid communication with the communicating channel in the lower bearing housing or in the pressure picker.

Preferably, the connecting pipe is arranged horizontally or obliquely.

Another aspect of the disclosure provides a rotary machine, comprising a shell including an oil sump for receiving lubricating oil; a rotary shaft disposed in the shell, wherein the rotary is provided therein with a thorough hole extending in an axial direction of the rotary shaft and the rotary shaft is in fluid communication with the oil sump via the through hole; and an oil level sensor in fluid communication with the through hole in the rotary shaft through a pressure picking passage.

Preferably, the rotary machine further comprises a bearing housing for supporting the rotary shaft, wherein the pressure picking passage comprises a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft, a circumferential oil groove formed on the rotary shaft or the bearing housing and in fluid communication with the pressure picking hole, and a communication channel extending through the bearing housing and in fluid communication with the circumferential oil groove and the oil level sensor.

Preferably, the rotary machine further comprises a pressure picker disposed between the rotary shaft and the oil level sensor, wherein the pressure picking passage comprises a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft, a circumferential oil groove formed on the rotary shaft or the pressure picker and in fluid communication with the pressure picking hole, and a communicating channel extending through the pressure picker and in fluid communication with the circumferential oil groove and the oil level sensor.

Technical Effects

The advantages of the rotary compressor and the rotary machine according to one or more embodiments of the present disclosure are as follows:

The compressor or the rotary machine is provide therein with an oil level detecting mechanism, therefore lubricating oil in the compressor or the rotary machine can be detected timely, accurately and reliably to prevent or reduce the damage of the compressor or the rotary machine due to insufficient lubricating oil.

The oil level detecting mechanism may include an oil level sensor and a pressure picking passage in fluid communication with the through hole in the rotary shaft, and the oil level sensor may be a pressure sensor or a pressure switch. Thereby, the oil level detecting mechanism may have a relatively simple configuration and may be machined easily, which reduces the cost of the compressor or the rotary machine.

In one or more embodiments of the disclosure, the lubricating oil in the compressor or the rotary machine can be detected more easily and reliably by converting the oil level detecting in the compressor or the rotary machine into hydraulic pressure detecting. And the expensive liquid level sensor can be replaced by a pressure sensor or a pressure switch having simpler configuration and lower cost.

A lubricating oil level to be detected can be adjusted more easily by controlling the length of the pressure picking pipe or the height of the pressure picking hole. Therefore, it is applicable in various types or models of compressor or rotary machine more easily.

The oil level sensor in one or more embodiments of the disclosure has relatively simple configuration and low cost, but has high reliability and short response time.

The first contact of the oil level sensor includes a plurality of pins spaced with each other, and the ON signal may be output as long as any one of the pins contact the piston head. Therefore, the reliability of the oil level sensor is enhanced.

The oil level sensor may be disposed inside or outside the shell of the compressor, and the oil level sensor may communicate directly with the pressure picking passage or communicate with the pressure picking passage through an additional pipeline, thereby greatly facilitating the arrangements of the components in the compressor.

The rotary compressor in one or more embodiments of the present disclosure provides not only an oil level sensor but also an oil temperature sensor, thus can provide multi-protection for the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of one or more embodiments of the disclosure will become more apparent with reference to the description in conjunction with the accompanied drawings in which:

FIG. 1 is a schematic sectional view of the rotary compressor according to an embodiment of the disclosure;

FIG. 2 is an enlarged view of a lower portion of the rotary compressor shown inFIG. 1;

FIG. 3 is a schematic diagram of an oil level detecting mechanism according to the embodiment of the disclosure;

FIG. 4 is a perspective view of a lower bearing integrated with an oil level sensor according to the embodiment of the disclosure;

FIG. 5 is an oil fork provided in the rotary compressor according to the embodiment of the disclosure;

FIG. 6 is a front view of an oil level sensor according to the embodiment of the disclosure;

FIG. 7 is a sectional view of an oil level sensor according to the embodiment of the disclosure, showing the oil level sensor in an OFF status;

FIG. 8 is a sectional view of an oil level sensor according to the embodiment of the disclosure, showing the oil level sensor in an ON status;

FIG. 9 is a schematic diagram of an oil level detecting mechanism according to another embodiment of the disclosure;

FIG. 10 is a schematic diagram of a variant of the oil level detecting mechanism according to another embodiment of the disclosure;

FIG. 11 illustrates the relationships among a lowest protection lubricating oil level, an inner radius of the rotary shaft, height of a pressure picking pipe and length of the pressure picking pipe;

FIG. 12 is a schematic diagram of an oil level detecting mechanism according to still another embodiment of the disclosure; and

FIGS. 13A and 13B are schematic sectional views of a lower portion of the rotary compressor according to a further embodiment of the disclosure.

DETAILED DESCRIPTION

The following description of the preferred embodiments is only illustrative rather than limiting the present disclosure and application or use thereof.

The basic configuration of the rotary compressor according to the present disclosure will be described with reference toFIG. 1 hereinafter.FIG. 1 is a schematic sectional view of a rotary compressor according to an embodiment of the disclosure. The rotary compressor shown inFIG. 1 is a scroll compressor, however, it should be appreciated by those skilled in the art that the present disclosure is not limited to the scroll compressor as shown, but may be applicable in other types of compressor with a rotary shaft, such as a screw compressor, a rotor compressor and so forth, and any types of rotary machine with a rotary shaft. In addition, the present disclosure is applicable not only in a vertical compressor with a rotary shaft oriented vertically but in a horizontal compressor with a rotary shaft oriented horizontally.

Therotary compressor10 includes a generallycylindrical shell12. An inlet fitting13 for sucking gaseous refrigerant in low pressure is provided on theshell12. One end of theshell12 is connected fixedly with anend cover14. Theend cover14 is fitted with a dischargingfitting15 for discharging compressed refrigerant. Amuffler plate16 extending transversely relative to an axial direction of the shell12 (approximately extending in the horizontal direction inFIG. 1) is provided between theshell12 and theend cover14, to divide an inner space of the compressor into a high side and a low side. The space between theend cover14 and themuffler plate16 acts as the high side space and the space between themuffler plate16 and theshell12 acts as the low side space. A part of theshell12 functions as an oil sump for receiving lubricating oil. In the example shown inFIG. 1, the oil sump is located at a lower portion of theshell12.

Theshell12 has acompressing mechanism20 and adriving mechanism30 housed therein. In the example shown inFIG. 1, thecompressing mechanism20 includes anon-orbiting scroll component22 and anorbiting scroll component24 which are engaged with each other. Thedriving mechanism30 includes amotor40 and arotary shaft50. Themotor40 includes astator42 and arotor44. Thestator42 is connected fixedly with theshell12. Therotor44 is connected fixedly with therotary shaft50 and rotates within thestator42. The first end (the upper end inFIG. 1) of therotary shaft50 is provided with aneccentric crank pin52 and the second end (the lower end inFIG. 1) of therotary shaft50 may includes aconcentric hole54. Theconcentric hole54 extends to theeccentric crank pin52 at the first end of therotary shaft50 via aneccentric hole56 offset radially with respect to theconcentric hole54. Therotary shaft50 is in fluid communication with the oil sump through theconcentric hole54.

The first end of the rotary50 is supported by amain bearing housing60 and the second end thereof is supported by alower bearing housing70. Themain bearing housing60 and thelower bearing housing70 are connected fixedly to theshell12 in proper ways. Theeccentric crank pin52 of therotary shaft50 is inserted into thehub26 of theorbiting scroll component24 via abush58 to rotatably drive the orbitingscroll component24.

The second end (the lower end inFIG. 1) of therotary shaft50 may further be provided with anoil pumping mechanism80. In the example shown inFIG. 1, theoil pumping mechanism80 may include a plate with ahole82 provided at the second end of therotary shaft50 and anoil fork84 provided in theconcentric hole54 and rotating along with therotary shaft50. The plate with ahole82 is approximately a disc with a throughhole83 provided centrally.FIG. 5 shows an example of theoil fork84. As shown inFIG. 5, theoil fork84 includes an approximatelyrectangular base86,legs87 and88 extending in the same direction from thebase86 and branched. Planes on which thelegs87 and88 lie are inclined with respect to a plane on which the base lies in a rotary direction A of therotary shaft50, respectively.

The lubricating oil in the lower portion of theshell12 flows into theconcentric hole54 of therotary shaft50 through the throughhole83 of the plate with ahole82 when the compressor operates. The lubricating oil flows radially from the center of the plate with ahole82 to periphery of the plate with ahole82 and an inner wall of theconcentric hole54 under the centrifugal force. Being brought by thelegs87 and88 of theoil fork83 rotating with therotary shaft50, the lubricating oil is pumped upwardly and forms a shape which is approximately a paraboloid P in theconcentric hole54, as shown inFIG. 3. And then, the lubricating oil flows into theeccentric hole56 in fluid communication with theconcentric hole52 and arrives at an end of theeccentric crank pin52. After being discharged from the end of theeccentric crank pin52, the lubricating oil flows downwardly under the gravity and is splashed by various moving components and then lubricates and cools various moving components.

In the example shown inFIG. 1, the oil pumping mechanism consisting of the plate with ahole82 and theoil fork84 is used. However, those skilled in the art should understand that, the oil pumping mechanism is not limited to what described herein and may use any mechanisms that can supply lubricating oil to theconcentric hole54 of therotary shaft50. In addition, the oil pumping mechanism consisting of the plate with ahole82 and theoil fork84 shown inFIG. 1 may be replaced by a vane pump. Furthermore, in a horizontal compressor, an oil pipe extending from the high side to the concentric hole of the rotary shaft at the low side may be used as the oil pumping mechanism since most of the lubricating oil is stored in the high side (in this case, the high side acts as the oil sump described above), in this circumstance, the lubricating oil may be supplied by a pressure difference between the high side and the low side.

Besides, those skilled in the art should understand that, thecompressing mechanism20 and thedriving mechanism30 are not limited to the configurations shown in the figures. Instead, thecompressing mechanism20 may be a rotor compressing mechanism or a screw compressing mechanism and so forth, and thedriving mechanism30 may be a hydraulic driving mechanism, a pneumatic driving mechanism and various transmission driving mechanism provided inside the shell or outside the shell.

The following documents provide the other detailed information of the rotary compressor related to the embodiments of the present disclosure: CN201206549Y, US2009/0068048A1, US2009/0068045A1, US2009/0068044A1 and US2009/0068043A1. The entire disclosures of these documents are incorporated herein by reference.

There must be sufficient lubricating oil in the compressor so as to ensure the normal operation of the compressor. In other words, the compressor should be shut off when the amount of lubricating oil, for example, a height of a lubricating oil level, in the compressor is lower than a predetermined value, for example, a lowest protection lubricating oil level, to prevent the compressor from being damaged.

Hereinafter, an oil level detecting mechanism will be described with reference toFIGS. 1 to 8.FIG. 2 is an enlarged view of a lower portion of the rotary compressor inFIG. 1.FIG. 3 is a perspective view of an oil level detecting mechanism according to the embodiment of the present disclosure.FIG. 4 is a perspective view of a lower bearing integrated with an oil level sensor according to the embodiment of the present disclosure.

As shown inFIGS. 1 to 3, therotary compressor10 according to the embodiment of the present disclosure further includes an oillevel detecting mechanism100 provided in thecompressor10. The oillevel detecting mechanism100 according to the embodiment of the present disclosure may include anoil level sensor120 in fluid communication with theconcentric hole54 of therotary shaft50 through apressure picking passage110. In the example shown inFIG. 3, thepressure picking passage110 may include apressure picking hole112 extending through a side wall of therotary shaft50 in an approximately radial direction, acircumferential oil groove114 provided in thelower bearing housing70 and in fluid communication with thepressure picking hole112 and a communicatingchannel116 provided in thelower bearing housing70 extending through thelower bearing housing70 in an approximately radial direction and in fluid communication with thecircumferential oil groove114 and thefluid inlet122 of theoil level sensor120. Theoil level sensor120 may be provided at thelower bearing housing70 or near thelower bearing housing70. During the rotation of therotary shaft50, thepressure picking hole112 on therotary shaft50 also be rotated. Since thecircumferential oil groove114 is provided corresponding to the rotation path of thepressure picking hole112, thepressure picking hole112 can always be in fluid communication with thecircumferential oil groove114, and in turn always be in fluid communication with the communicatingchannel116, so as to introduce the fluid stably into theoil level sensor120 connected therewith.

FIG. 6 is a front view of an oil level sensor according to the embodiment of the present disclosure, wherein the housing of the oil level sensor is not shown in the figure.FIG. 7 is a sectional view of an oil level sensor according to the embodiment of the present disclosure, showing the oil level sensor in an OFF state.FIG. 8 is a sectional view of an oil level sensor according to the embodiment of the present disclosure, showing the oil level sensor in an ON state.

As shown inFIGS. 6 to 8, theoil level sensor120 may include an approximatelycylindrical housing121, apiston cap123 movable axially in thehousing121, apiston head125 moving with thepiston cap123, aterminal plug126 closing an end of thehousing121, afirst contact127 and asecond contact128 provided in theterminal plug126 and a return spring provided between thepiston head125 and theterminal plug126. Afluid inlet122 is provided on a side wall of an end of thehousing121 opposing to theterminal plug126 and adischarge outlet124 is formed on a side wall of theshell121. During the axial movement of thepiston head125, fluid between thepiston head125 and theterminal plug126 is discharged through thedischarge outlet124 to reduce resistance to the supplied fluid. Apiston rod125aof thepiston head125 extends through a throughhole131 formed in theterminal plug126 and is movable axially in the throughhole131. Thefirst contact127 may include a plurality ofpins127A and127B spaced with each other but connected with each other. In the example of the figures, thefirst contact127 includes twopins127A and127B, however, those skilled in the art should understand that, thefirst contact127 may include only one pin or more than two pins. Thesecond contact128 may include anannular contact lug128A. Theannular contact lug128A is provided on a step of theterminal plug126. Thereturn spring129 is connected electrically with theannular contact lug128A of thesecond contact128 and thepiston head125. Besides, as shown inFIG. 2, thefirst contact127 and thesecond contact128 of theoil level sensor120 lead to the outside of the compressor through anadaptor150 provided on theshell12.

As shown inFIG. 7, when there is no fluid supplied to theinlet122 of theoil level sensor120, thepiston head125, under the action of thereturn spring129, moves toward a direction opposing to thefirst contact127 and thesecond contact128, so as to disconnect thefirst contact127 and thesecond contact128. Meanwhile, theoil level sensor120 outputs no signals, or outputs a signal “0”.

As shown inFIG. 8, when fluid is supplied to theinlet122 of theoil level sensor120, thepiston head125, pushed by the fluid supplied, overcomes the force of thereturn spring129 and moves towards thefirst contact127 and thesecond contact128. When thepiston head125 contacts any one of the pins of thefirst contact127, thefirst contact127 and thesecond contact128 can be connected electrically. Then, theoil level sensor120 outputs an ON signal, or outputs a signal “1”.

A specific oil level sensor is illustrated inFIGS. 6 to 8. It should be appreciated by those skilled in the art that, the oil level sensor may be any kind of sensor including a fluid pressure receiving portion for receiving pressure of fluid and a converting portion for converting the pressure of fluid into an electric signal.

Hereinafter, the process of detecting lubricating oil in the rotary compressor according to the embodiment of the present disclosure will be described. When there is a proper amount of lubricating oil in theshell12 of the compressor, lubricating oil entering into theconcentric hole54 of therotary shaft50, under the action of centrifugal force, forms a paraboloid P as shown inFIG. 3. Then, the lubricating oil flows into thefluid inlet122 of theoil level sensor120 through thepressure picking hole112 on the side wall of the rotary shaft, thecircumferential oil groove114 formed in thelower bearing housing70 and the communicatingchannel116 in thelower bearing housing70. As described above, thepiston head125, being pushed by the lubricating oil, moves towards thefirst contact127 and thesecond contact128 and connect electrically thefirst contact127 and thesecond contact128 finally, so as to output the signal “1” which indicates that there is a proper amount of lubricating oil in the compressor. In contrary, if there is no sufficient amount of lubricating oil in theshell12 of the compressor, no lubricating oil arrives at theinlet122 of theoil level sensor120, therefore, theoil level sensor120 outputs the signal “0” which indicates that there is no sufficient amount of lubricating oil in the compressor.

In order to detect the lubricating oil level in the compressor more accurately, apressure picking pipe118 protruding towards an axis of theconcentric hole54 may be disposed in thepressure picking hole122 on a side wall of the rotary shaft. A lubricating oil level to be detected may be controlled by the length of thepressure picking pipe118 protruding inwardly (for example, the length L shown inFIGS. 9 and 11). As shown inFIG. 3, when adistal end119 of thepressure picking pipe118 is located within the oil surface denoted by the paraboloid P, lubricating oil is capable of flowing into thepressure picking pipe118. During the movement along thepressure picking pipe118, kinetic energy of the lubricating oil can be converted into the pressure, thereby a certain pressure difference is produced between the both ends of thepressure picking pipe118. When lubricating oil with a certain pressure flows into theoil level sensor120, thepiston head125 of theoil level sensor120 is pushed thereby connecting electrically thefirst contact127 and thesecond contact128, and thus the sensor outputs the signal “1”. If thedistal end119 of thepressure picking pipe118 is located outside the oil surface donated by the paraboloid P, lubricating oil cannot flow into theoil level sensor120 and thus the sensor outputs the signal “0”. Accordingly, when a lubricating oil level to be detected (i.e. a lowest protection lubricating oil level) is set higher, a longerpressure picking pipe118 may be used, while when a lubricating oil level to be detected (i.e. a lowest protection lubricating oil level) is set lower, a shorterpressure picking pipe118 may be used. Particularly, the relationship between the lowest protection lubricating oil level and a length of thepressure picking pipe118 when the compressor is operated in a certain working state may be determined by calculation or experiment.

Specifically referring toFIG. 11, the lower protection lubricating oil level and the length of thepressure picking pipe118 may satisfy the following equation:

$H=h-\frac{{\left(R-L\right)}^2·{\left(\frac{\mathrm{<figure-callout\; label="n"\; filenames="US09850900-20171226-D00001.png"\; state="\{\{state\}\}">n</figure-callout>}}{60}·2\pi \right)}^2}{2000·g},$

wherein, H [mm] is a height of the lowest protection lubricating oil level from an end face S0 of therotary shaft50;

L [mm] is a length of thepressure picking pipe118 protruded into therotary shaft50;

R [mm] is an inner radius of therotary shaft50;

h [mm] is a height of a center axis of thepressure picking pipe118 from the end face S0 of therotary shaft50;

n [rpm] is the number of revolution of the rotary shaft; and

g [m/s²] is the acceleration of gravity.

According to the above equation, for example, if h=32 mm, L=6.9 mm, n=2000 rpm, R=9 mm, g=9.81 m/s², then H≈22 mm. That is, when the number of revolution of the rotary shaft is 2000 rpm and the length of the pressure picking pipe protruded into the rotary shaft is 6.9 mm, the lowest protection lubricating oil level that can be detected by the oil level sensor is about 22 mm. That is, when the lubricating oil level in the oil sump is higher than 22 mm, the oil level sensor can output the signal “1”, indicating that the compressor can operate normally. And when the lubricating oil level in the oil sump is lower than 22 mm, the oil level sensor cannot output the signal “1” (i.e. it outputs the signal “0”), indicating that there is no sufficient lubricating oil in the compressor, then a compressor protection mechanism would shut off the compressor.

Except the method of providing the pressure picking pipe mentioned above, a lubricating oil level in the compressor may be detected more accurately by adjusting the height h of thepressure picking hole112 from a certain reference surface (for example, the reference surface S inFIG. 9, it may be a bottom surface of the compressor, and also may be an end surface S0 of the rotary shaft50). In particularly, when a lubricating oil level to be detected (i.e. a lowest protection oil level) is set higher, the height of thepressure picking hole112 from a certain reference surface may be set higher, and when a lubricating oil level to be detected (i.e. a lowest protection oil level) is set lower, the height of thepressure picking hole112 from a certain reference surface may be set lower. Specifically, the relationship between a lubricating oil level to be detected and a height of thepressure picking hole112 from a certain reference surface when the compressor is operated in a certain working state may be determined by calculation or experiment.

In the example shown inFIG. 3, thepressure picking passage110 includes apressure picking hole112 provided on a side wall of the rotary shaft, acircumferential oil groove114 provide in alower bearing housing70, a communicatingchannel116 extending through thelower bearing housing70, and optionally includes apressure picking pipe118 provided in thepressure picking hole112. However, the configuration of thepressure picking passage110 is not limited to what described herein, but can have various variants. For example, thecircumferential oil groove112 may be provided on therotary shaft50, rather than provided on thelower bearing housing70. In addition, for example, as shown inFIGS. 9 and 10, apressure picker130 may further be provide between therotary shaft50 and theoil level sensor120. In the example shown inFIG. 9, thepressure picker130 is an annular element and includes acircumferential oil groove114A in fluid communication with thepressure picking hole112 on therotary shaft50 and a communicatingchannel116A in fluid communication with thecircumferential oil groove114A and extending through thepressure picker130. In the example shown inFIG. 10, acircumferential oil groove114B may be disposed on therotary shaft50. Thefluid inlet122 of theoil level sensor120 may be in fluid communication with the communicatingchannel116A of thepressure picker130 directly or through other pipelines. Theoil level sensor120 may be arranged more flexibly by providing thepressure picker130, and the configuration of thelower bearing housing70 needn't be modified.

In an example of the oil level detecting mechanism according to the present disclosure shown inFIG. 11, anoil temperature sensor140 may be provided further. Theoil temperature sensor140 and theoil level sensor120 may use acommon lead wire142. In particularly,lead wires141 and142 output signals of theoil level sensor120, and leadwires142 and143 output signals of the oil temperature sensor. In this embodiment, the compressor may be controlled not only based on signals of theoil level sensor120 but also based on signals of theoil temperature sensor140. Thus it provides double protection for the compressor.

In the embodiments shown in the figures, the oillevel detecting mechanism100 is in fluid communication with theconcentric hole54. However, it should be understood by those skilled in the art that, theconcentric hole54 may be replaced by an eccentric hole extending axially along therotary shaft50. Besides, basing on the inner design of the compressor, the oillevel detecting mechanism100 may be in fluid communication with theeccentric hole56 of therotary shaft50. Even if theholes54 and56 are all eccentric holes, the oil level detecting mechanism of the disclosure still can operate normally because of the centrifugal force caused by rotation of the rotary shaft.

In the embodiments of the disclosure, an oil level sensor including a piston, contacts and a spring is described. Those skilled in the art should understand that, any suitable pressure sensor known in the art, specifically a pressure switch, may be used as the oil level sensor.

In the embodiments mentioned above, theoil level sensor120 is illustrated to be disposed in theshell12 and can be in fluid communication with the communicatingchannel116 in thelower bearing housing70 or the communicatingchannel116A in thepressure picker130 directly or by an additional pipeline. However, the present disclosure is not limited to what is described herein. As shown inFIGS. 13A and 13B, theoil level sensor120 may be provided outside theshell12 and in fluid communication with the communicatingchannel116 in the lower bearing housing70 (or a communicating channel in the pressure picker) through the connectingpipe160. The connectingpipe160 may be arranged horizontally (as shown inFIG. 13A) or be arranged obliquely (as shown inFIG. 13B). With this kind of configuration, the various components within the compressor can be arranged more flexibly.

While various embodiments of the present disclosure have been described in detail herein, it should be understood that the present disclosure is not limited to the specific embodiments described in detail and illustrated herein, those skilled in the art can make other variants and modifications without departing from the principle and scope of the present disclosure. All these variants and modifications fall into the scope of the present disclosure. Furthermore, all the elements described herein can be replaced by the other technically equivalent elements.

Claims (37)

What is claimed is:

1. A rotary compressor, comprising:

a shell including an oil sump for receiving lubricating oil;

a compressing mechanism disposed in the shell;

a driving mechanism for driving the compressing mechanism, wherein the driving mechanism includes a rotary shaft provided therein, the rotary shaft having a through hole extending in an axial direction therein and being in fluid communication with the oil sump via the through hole; and

an oil level sensor in fluid communication with the through hole in the rotary shaft through a pressure picking passage such that lubricating oil can flow from the through hole in the rotary shaft through the pressure picking passage to the oil level sensor, wherein the oil level sensor is adapted to sense a level of lubricating oil in the oil sump in response to a pressure of the lubricating oil,

wherein the pressure picking passage further includes a pressure picking pipe disposed in the pressure picking passage that selectively permits the flow of the lubricating oil to the oil level sensor based on a pressure of the lubricating oil.

2. The rotary compressor according toclaim 1, further comprising a lower bearing housing for supporting the rotary shaft,

wherein the pressure picking passage comprises:

a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft,

a circumferential oil groove formed on the rotary shaft or the lower bearing housing and in fluid communication with the pressure picking hole, and

a communicating channel extending through the lower bearing housing and in fluid communication with the circumferential oil groove and the oil level sensor.

3. The rotary compressor according toclaim 2, wherein the pressure picking pipe is disposed in the pressure picking hole and protruded toward an axis of the through hole in the rotary shaft.

4. The rotary compressor according toclaim 3, wherein a length of the pressure picking pipe is determined according to a lowest protection lubricating oil level in the oil sump.

5. The rotary compressor according toclaim 4, wherein the higher the lowest protection lubricating oil level is set, the longer the length of the pressure picking pipe is set.

6. The rotary compressor according toclaim 4, the lowest protection lubricating oil level and the length of the pressure picking pipe satisfy the following equation:

$H=h-\frac{{\left(R-L\right)}^2·{\left(\frac{n}{60}·2\pi \right)}^2}{2000·g},$

wherein, H [mm] is a height of the lowest protection lubricating oil level from an end face of the rotary shaft;

L [mm]—a length of the pressure picking pipe protruded into the rotary shaft (50);

R [mm]—an inner radius of the rotary shaft;

h [mm]—a height of a center axis of the pressure picking pipe from the end face of the rotary shaft;

n [rpm]—the number of revolution of the rotary shaft; and

g [m/s²]—the acceleration of gravity.

7. The rotary compressor according toclaim 2, wherein a height of the pressure picking hole from a certain reference surface is determined according to a lowest protection lubricating oil level in the oil sump.

8. The rotary compressor according toclaim 7, wherein the higher the lowest protection lubricating oil level is set, the higher the height of the pressure picking hole is set.

9. The rotary compressor according toclaim 7, wherein the reference surface is a bottom surface of the rotary compressor or an end surface of the rotary shaft.

10. The rotary compressor according toclaim 2, wherein the oil level sensor is provided to be closer to the lower bearing housing than a main bearing housing.

11. The rotary compressor according toclaim 2, wherein the oil level sensor is directly connected with the communicating channel in the lower bearing housing.

12. The rotary compressor according toclaim 2, wherein the oil level sensor is connected with the communicating channel in the lower bearing housing through an additional pipeline.

13. The rotary compressor according toclaim 2, wherein the oil level sensor is disposed inside the shell.

14. The rotary compressor according toclaim 2, wherein the oil level sensor is disposed outside the shell.

15. The rotary compressor according toclaim 14, wherein the pressure picking passage further comprises a connecting pipe in fluid communication with the communicating channel in the lower bearing housing.

16. The rotary compressor according toclaim 15, wherein the connecting pipe is arranged horizontally or obliquely.

17. The rotary compressor according toclaim 1, further comprising a pressure picker disposed between the rotary shaft and the oil level sensor,

wherein the pressure picking passage comprises:

a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft,

a circumferential oil groove formed on the rotary shaft or the pressure picker and in fluid communication with the pressure picking hole, and

a communicating channel extending through the pressure picker and in fluid communication with the circumferential oil groove and the oil level sensor.

18. The rotary compressor according toclaim 17, wherein the oil level sensor is directly connected with the communicating channel in the pressure picker.

19. The rotary compressor according toclaim 17, wherein the oil level sensor is connected with the communicating channel in the pressure picker through an additional pipeline.

20. The rotary compressor according toclaim 17, wherein the oil level sensor is disposed outside the shell.

21. The rotary compressor according toclaim 20, wherein the pressure picking passage further comprises a connecting pipe in fluid communication with the communicating channel in the pressure picker.

22. The rotary compressor according toclaim 1, further comprising an oil pumping mechanism, wherein the oil pumping mechanism includes a plate with a hole provided at an end of the rotary shaft and an oil fork provided in the through hole of the rotary shaft.

23. The rotary compressor according toclaim 1, further comprising an oil pumping mechanism, wherein the oil pumping mechanism includes a vane pump provided at an end of the rotary shaft.

24. The rotary compressor according toclaim 1, wherein the rotary compressor is a horizontal rotary compressor and an inner space of the rotary compressor is divided into high side acting as the oil sump and low side by a muffler plate, and

wherein the rotary compressor further comprises an oil pumping mechanism, and the oil pumping mechanism is an oil pipe extending from the oil sump to the through hole in the rotary shaft.

25. The rotary compressor according toclaim 1, wherein the through hole comprises a concentric hole portion which is concentric with respect to the rotary shaft and an eccentric hole portion which is offset radially with respect to the concentric hole.

26. The rotary compressor according toclaim 1, wherein the oil level sensor is a pressure sensor.

27. The rotary compressor according toclaim 1, wherein the oil level sensor is a pressure switch.

28. The rotary compressor according toclaim 1, wherein the oil level sensor comprises:

a fluid pressure receiving portion for receiving pressure of fluid, and

a converting portion for converting the pressure of fluid into an electrical signal.

29. The rotary compressor according toclaim 28, wherein the fluid pressure receiving portion comprises: a housing; and a piston head which is movable axially in the housing;

wherein the converting portion comprises: a terminal plug; a first contact and a second contact provided in the terminal plug; and a spring for providing electrical connection between the piston head and the second contact and providing return force for the piston head, and

wherein the oil level sensor outputs the electrical signal when the piston head contacts the first contact.

30. The rotary compressor according toclaim 29, wherein the first contact comprises a plurality of pins which are spaced with each other.

31. The rotary compressor according toclaim 29, wherein the second contact comprises an annular contact lug electrically contacted with the spring.

32. The rotary compressor according toclaim 1, further comprising an oil temperature sensor.

33. The rotary compressor according toclaim 32, wherein the oil temperature sensor and the oil level sensor have a common lead wire.

34. The rotary compressor according toclaim 1, wherein the rotary compressor is a scroll compressor, or a screw compressor, or a rotor compressor.

35. A rotary machine, comprising:

a shell including an oil sump for receiving lubricating oil;

a rotary shaft disposed in the shell, the rotary shaft having a through hole extending in an axial direction therein and being in fluid communication with the oil sump via the through hole; and

an oil level sensor in fluid communication with the through hole in the rotary shaft through a pressure picking passage such that lubricating oil can flow from the through hole in the rotary shaft through the pressure picking passage to the oil level sensor, wherein the oil level sensor is adapted to sense a level of lubricating oil in the oil sump in response to a pressure of the lubricating oil,

wherein the pressure picking passage further includes a pressure picking pipe disposed in the pressure picking passage that selectively permits the flow of the lubricating oil to the oil level sensor based on a pressure of the lubricating oil.

36. The rotary machine according toclaim 35, further comprising a bearing housing for supporting the rotary shaft,

wherein the pressure picking passage comprises a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft, a circumferential oil groove formed on the rotary shaft or the bearing housing and in fluid communication with the pressure picking hole, and a communicating channel extending through the bearing housing and in fluid communication with the circumferential oil groove and the oil level sensor.

37. The rotary machine according toclaim 35, further comprising a pressure picker disposed between the rotary shaft and the oil level sensor,

wherein the pressure picking passage comprises a pressure picking hole extending through a side wall of the rotary shaft and in fluid communication with the through hole in the rotary shaft, a circumferential oil groove formed on the rotary shaft or the pressure picker and in fluid communication with the pressure picking hole, and a communicating channel extending through the pressure picker and in fluid communication with the circumferential oil groove and the oil level sensor.

Images